Inconsequential ramblings of an Old Git

[mangocrazy]

So while I'm waiting to stick the VFR on the dyno, and the weather is still shit, I thought I'd bugger about with the LC. Just because.

The LC has a YSS shock on it, which is a massive improvement on the 40 year old thing that supported the rear of the bike before. But after a fair amount of running, I've realised that a) the spring is a bit on the harsh side for my tender little botty and b) I'd like some more weight on the front to make it feel a little less vague.

As regards the spring, YSS ship the shock with an 80 Nm (or is that N/mm?) item. They also offer a 70 and a 90 spring in the same sizes for lighter and heavier riders respectively. So I've placed an order for a 75 Nm with a local spring supplier, just to be a fussy bastard. Delivery should be mid-March.

To try and fix the perceived 'weight on front' problem, I've acquired some 25mm alloy round bar and handed it to my local engineering place, along with a CAD drawing and asked them to make it happen. This is what I got back:

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These fit in between the top shock eye and the shock body and increase the overall length of the shock by anything between 25 and 40mm, thereby jacking the back end of the bike up by a similar amount. The piece with the shorter nose gives a minimum increase of 25mm in shock length, the one with the longer nose and thin nut gives a minimum increase of 30mm in shock length. If you really wanted to you could increase the shock length by at least another 15mm, but frankly it's all getting a bit silly at those settings. This is a pic of the shock with short extension mounted on the bike:

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To be honest, the extension piece with the short nose is probably at the outer limits of sensible modification. With that fitted, the centre stand is largely redundant as it needs to be stood on a piece of 18mm ply to actually get the rear wheel off the ground. I'm also planning to drop the forks through the yokes by 10mm to lower the front and hopefully bring the centre stand back into use. Thankfully the LC also has a side stand, but the bike now sits at quite a jaunty angle when using that (see below). At least it won't blow over in the wind...

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And after all this I still don't know what effect these mods will have on the handling. I'll learn that in due course... But all the mods are completely reversible, so not all is lost if it fails horribly...

[Le_Fromage_Grande]

If my memory of 1987ish is correct LCs handle better with the front end dropped by 20mm and it doesn't make a noticeable difference to ground clearance, as it's the fat part of the pipes that scrape in corners.

[mangocrazy]

If my memory of 1987ish is correct LCs handle better with the front end dropped by 20mm and it doesn't make a noticeable difference to ground clearance, as it's the fat part of the pipes that scrape in corners.

Cheers. I'll start at 10mm and add droppage as required...

[mangocrazy]

As an illustration of how the spacer has lifted the back end, here's a photo of the bike on an 18mm deep ply board, and the rear tyre is just clear of the ground (by about 5mm). There's also a lot more air between the rear tyre and the mudguard than previously...

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[mangocrazy]

Today dawned bright and sunny (as forecast) and so the LC was wheeled out blinking into the sunlight, had its tyres pumped up and we then went for an enjoyable little jaunt around some south Yorkshire/north Derbyshire scenery. None of which I can show you, as I didn't take a camera and my dumb phone doesn't have any photographic capabilities (or any other capabilities, if I'm honest).

This was the bike's (and my) first outing this year and it was the first time I'd ridden it with the lengthened shock and slightly softer shock spring. I was also wearing new boots and helmet so was taking it steady until I had a few miles under the wheels. But within a hundred yards or so it was obvious that the shock felt much better - more compliant and no sharp kicks up the spine over harsh bumps. To be honest the handling and steering wasn't that much different with the longer shock, just a more composed and balanced feeling. There were certainly no vicious tank-slappers or terminal instability, in fact the whole plot (if anything) felt more stable than previously.

Anyway, here are some photos of the old girl in the back garden, but fully clothed this time.

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and side view:

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And in other news, I've finally bought a phone with a camera!


But it's still dumb, and a flip-phone...

[mangocrazy]

Today was dyno-day...! At 9 am I pulled up outside John Warrington's emporium in Malton (on the A64 between York and Scarborough) with the VFR in the van. I've fitted a pair of aftermarket exhausts and was a little concerned that they might have made the bike run lean, plus I've been twatting about with a Sigma jet kit and wanted to know whether the carburation was OK or miles off, and if it was off, in which direction (rich or lean).

I'd scarcely popped my head round the door before I was offered a cup of tea, so things definitely got off on the right foot. And then before we got down to running the bike, John talked me through the technicalities of the dyno and the principles of how it all worked. Maths and physics, basically. Then it was time to get the bike strapped down and screaming for mercy. John warmed the bike up in stages and was initially interested in seeing what the low speed and mid range fuelling was like. Seriously on the rich side, it transpired. Not at all what I'd expected. It also highlighted that there was an exhaust blow on the LH side of the bike that will need sorting, that side running noticeably leaner than the RH side. But still rich, IYSWIM.

I don't know how many of you have ever removed and re-fitted a bank of V4 carburettors, but trust me - it's an absolute twat of a job. You really don't do it unless you absolutely have to. So John suggested we just work on the (relatively accessible) rear pair of carbs. Without removing them from the bike it's a simple job to take the carb tops off and remove the diaphragms and needle assembly. As part of the Sigma kit, they had supplied washers to fit under the head of the needle (the needles dont have any adjustment notches - thanks Honda...), thereby richening the mixture. I'd fitted two washers per needle which had the approximate effect of rasing the needle by the equivalent of one notch.

The Sigma kit also supplied a drill bit with which you were instructed to drill out and enlarge the two small holes in the base of the needle holder. I'd followed orders and done this, but John was not at all impressed. His view was that the extra hole surface area would mean that the slides would be less likely to lift with the intake air pressure, thereby further richening the mixture. There wasn't much we could do about that at that time, but I will need to look around in my spares box and see if I can find a set of unmolested slides/diaphragms.

With the back needles effectively dropped one notch it was time to run 'er up on the dyno again. This time the Air/fuel mixture was noticeably less rich than before, but still too rich for John's liking. This was with the needle washers removed on only 2 of the 4 carbs, so there were still improvements to be found by correcting the other two needle positions. I'm also intending to renew all the float valves and seats, as doing that on the LC made a big improvement. Lastly I may also try and find some NOS emulsion tubes on the basis that the current ones must have some wear after 50k miles and that would also contribute to richening of the mixture. Unfortunately they've been discontinued by Honda and are rare as hen's teeth.

So it was a really instructive day, and has definitely shown me a way forward. And to leave on a positive note, the 36 year old bike with 50k + miles on the clock, rich fuelling and a leaky exhaust registered a very healthy 94 bhp! I was expecting mid-80s, so that was a nice surprise.

Time to dig out the big box marked 'VFR stuff' and get ordering carby parts...

[mangocrazy]

Welcome to a time-warp 1980s shed somewhere in Sheffield...

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[Supermofo]

94 is healthy numbers for such an old bike, it'd see off the latest crop of 750/800 shopping bikes. Never ridden the 750 but loved my dad's 800, they are a bargain now too but definitely not ULEZ I'd imagine. Although a really old 750 must be close to exempt!

[mangocrazy]

94 is healthy numbers for such an old bike, it'd see off the latest crop of 750/800 shopping bikes. Never ridden the 750 but loved my dad's 800, they are a bargain now too but definitely not ULEZ I'd imagine. Although a really old 750 must be close to exempt!

The newer 750/800s would have the advantage of being lighter (something I'm starting to notice more as I get older). My old VFR weighs 203kg dry, so it's a bit of a lardy old lump, but it should be eligible for Historic Vehicle status in 2028 and thereby ULEZ exempt. But it does make lovely linear power. The dyno power curve was pretty much a straight line (didn't ask for a copy, foolishly).

Once I've done all the carb mods I'll be taking it back to John for a re-test, but that won't be until mid summer. I'll get a print-out then. The 800s were the first of the EFI models, weren't they? ISTR that only the 750s had carbs.

[Skub]

Since it was after the pic of the Elsie,I thought for a moment you had squeezed 94bhp out of it.

That would be quite something.

There's nothing like a well set up bike on a dyno. Folk have this idea it's all about big numbers and outright performance,but owning a bike that has sweet fueling everywhere is cause for deep joy.

[mangocrazy]

Absolutely this ^^. The amount of time you spend at WOT is infinitesimal - 0.001% if that on a road bike. You spend all your time either on the slow running jets or the needle and that's what needs attention. Deciding on main jet size is a pretty simple thing, the rest of it most certainly is not.

A standard LC with 94 bhp would be an utter death-trap...

[Mr. Dazzle]

The 800s were the first of the EFI models, weren't they? ISTR that only the 750s had carbs.

Indeed they were. My Dad had a bright red X reg (so.....99?) 800 from brand new. I still remember the PGM-FI text under the VFR logo on the fairing.

IIRC it was also the first one with linked brakes.

I had an RC36a, which again IIRC was the last one with carbs.

[mangocrazy]

The 800s were the first of the EFI models, weren't they? ISTR that only the 750s had carbs.

Indeed they were. My Dad had a bright red X reg (so.....99?) 800 from brand new. I still remember the PGM-FI text under the VFR logo on the fairing.

IIRC it was also the first one with linked brakes.

I had an RC36a, which again IIRC was the last one with carbs.

The early RC36 (a?) were the FL/FM/FN/FP models (1990/91/92/93) and the later RC36 (b?) were the FR/FS/FT/FV models (1994/95/96/97). I had an FT, and it was immensely capable (and probably the best looking of the 750s) but it always felt a bit flat to me compared to the older and lighter conventional swingarm models. Honda had traded a little bit of top end for increased mid-range to compensate for the increased weight, I think.

[Mr. Dazzle]

I always say a when I mean b. I had a 1995, one of the last ever 750 types.

[mangocrazy]

One area where the RC36 was streets ahead of the RC24 (conventional swingarm) was in the headlights. I couldn't believe how much better the lights were when I switched from an RC24 to an RC36.

[Mr. Dazzle]

Daddy dazzle also had one of the newer VFR800s with the LED headlights (he also had one of the early noughties VTECs...bit of a theme ).

Those are blooming impressive for bike lights!

[mangocrazy]

Yes, I remember it being commented on in the road tests of the time. I kinda lost interest in VFRs when they ditched the gear driven cams - for me they were the essence of VFR-dom. I can understand why they did - they're expensive to manufacture - but it diminished them in my eyes. And then going from DOHC to SOHC with the 1200, and having the chutzpah to label it 'Unicam' (!), completed the fall from grace. A mate of mine had a VFR1200 and he loved it, but it wasn't for me. Too bloody heavy, as well.

[Mr. Dazzle]

TBF there's quite a lot more to the VFR1200 engine than the switch the SOHC! It's still a 4v head too AFAIK.

It's got a properly Honda approach to alot of to it, in that it's "just because we can" type design. It's something odd like 30° firing interval, the cylinders are laid out differently so the rear pair are closer together and take up less space, the SOHC means its mounted really low down etc.

I don't remember many details, but I do remember thinking they'd gone to enormous lengths!

[mangocrazy]

Yeah, it had been rumoured for ages, so it had a long development time and as you say, it was chock full of Honda 'innovation' (whether that was a good thing or not). I do remember there being a spate of seized preload adjusters on the shock, and the suspension in general was regarded as being not quite up to the standard of the rest of the bike, but that's a common enough complaint on a lot of Japanese bikes. I found it quite odd that Honda spent so much R&D on the bike, only for it to be discontinued as it wouldn't meet upcoming Euro5 standards. Wouldn't they have been aware of that being imminent?

[mangocrazy]

3 or 4 years ago, when I was reassembling/partially restoring my 350LC, one of the things I had done was to get the plate on which the clocks sat re=plated. As with a lot of fasteners on the LC, they had been finished in olive-green drab passivate (zinc coating), and over time that had corroded. Fortunately I knew someone who could get this done (apparently the process is sufficiently hazardous to health that only the military have ready access to it), but to get the plate off the clocks meant partially disassembling them...

As soon as I'd taken the backplate off I knew I was in trouble, and so it proved. When the plate came back all new and drab and I tried to reassemble everything it was as much as I could do to get the back on without trapping any of the small wires that fed the idiot lights. When it came to start the bike up I though I had a flat battery as none of the dash lights would come on. But the engine started and headlights and indicators worked, but the dash lights either didn't work or worked when they felt like it.

Once again the RDLC-Crazy forum came to the rescue in the shape of one Shaun Murphy. According to all the forum members he was The Man to fix clocks, in much the same as Gary (Arrow on the forum) is The Man for oil pumps. So, as I'm going to be in France for 5 weeks very soon and the LC would be staying put in Blighty it was time to remove the clocks, parcel them up with much padding and send them off to Shaun on Monday. That will mean I'll have a set of working clocks and idiot lights ready for me when I come back. That thought makes me happy.